In aqueous environments, such as lakes, that normally have a balance of predator and prey fish (also referred to as bait fish) populations, the prey fish are abundant enough to adequately support the predator fish population. The predator fish, which generally are desirable game or sport fish, are in turn usually caught in sufficient numbers by fishermen to maintain control over the number of their population.
Under various circumstances, however, an imbalance may occur in which the game fish significantly outnumber the prey fish, which are then consumed at a rate such as to threaten the continued existence of the prey fish, which in turn threatens the future existence of the game fish. In addition, other various factors can independently affect the population of the prey fish, including changes in the water level, which may expose the prey fish spawning beds, and high water flow periods, which may wash prey fish downstream. Other weather and environmental factors can also have a detrimental effect on the number of prey fish.
In such circumstances, it is important to quickly reduce the number of predator fish. Historically, one method is to poison the entire body of water, and then restock with the appropriate numbers of predator and prey fish populations. U.S. Pat. No. 4,395,969 to Cheng and U.S. Pat. No. 4,221,782 to MacPhee are examples of such a method. In addition, in some cases, fishing regulations are temporarily modified in order to increase the number of predator/game fish caught by fishermen, thereby reducing the threat to the prey fish. However, this particular method has not proven to be a reliable or significant solution to the problem.
With respect to a solution, it is desirable to be able to reliably control/reduce the numbers of predator fish in a given body of water without having to completely poison the body of water.